The study reviews and examines the definitions of reactive power, apparent power, and power factor. Among the different definitions of power factor in three-phase circuits under a non-sinusoidal condition, this study adopts the definition of the effective power factor, which is also advocated by IEEE Standard 1459-2010. The effective power factor is defined as the ratio of the real power consumed by the load over the effective apparent power. The effective apparent power is the maximum power transmitted to the load (or delivered by a source) while keeping the same line losses and the same load (or source) voltage and current. The effective power factor theory gives apparent power a definite physical significance and provides more insights than other definitions in unbalanced circuits. Another merit of the effective power factor definition is that it only involves measurements and computations in the time domain. This study implements the computation of the effective power factor in MATLAB for use in PSCAD/EMTDC. The latter simulates the power system and provides three-phase voltage and current measurements. MATLAB performs the effective power factor computation and sends the results back to PSCAD. A number of simulations are provided in this report to demonstrate the validity and the accuracy of this implementation. / text

This thesis investigates single pole reclosing in series capacitor compensated line. An algorithm is developed to determine the optimal dead time required for single pole reclose of circuit breakers and to reduce the randomness of reclosing time. The algorithm considers conditions of system, fault, voltage zero crossing, arc, and IEEE C37.104-2012 standard de-ionization time. This study also addresses difficulties of single pole reclose operation such as over-voltages at the line, secondary arc extinguishing time, dead time, over-voltages across the series capacitor, and negative sequence current. The system performance is evaluated using a set of metrics based on those operation difficulties. Methods used in the industry such as shunt reactor with the neutral reactor, surge arrester, and MOV are modelled and simulated to capture their effect on the operation difficulties. Comparative analysis is made to rank the effectiveness of each element against difficulties in operating single pole reclosing of circuit breakers.

Maps are essential in the robots of today, not only to navigate but also to perform actions.This project’s aim was to create a program able to take map files of older standards suchas ROS Gridmaps or the current IEEE 2D map standard 1873-2015[2] and convert themto the new IEEE P2751/D1[4] standard. The new IEEE P2751/D1 is based of IEEE1873-2015 but improves by allowing 3D map formats such as Pointclouds or Voxel-gridsto be incorporated. This projects main goal was to have a program that is able to convertfrom some of these different map types into the new standard. The existence of sucha program eases any future adaptation. This report also includes a detailed evaluationof the efficiency of the IEEE P2751/D1 standard format in comparison to other mapformats.

The purpose of this thesis is to present solutions to overcome several key difficulties that limit the application of numerical modelling in communication cable design and analysis. In particular, specific limiting factors are that simulations are time consuming, and the process of comparison requires skill and is poorly defined and understood. When much of the process of design consists of optimisation of performance within a well defined domain, the use of artificial intelligence techniques may reduce or remove the need for human interaction in the design process. The automation of human processes allows round-the-clock operation at a faster throughput. Achieving a speedup would permit greater exploration of the possible designs, improving understanding of the domain. This thesis presents work that relates to three facets of the efficiency of numerical modelling: minimizing simulation execution time, controlling optimization processes and quantifying comparisons of results. These topics are of interest because simulation times for most problems of interest run into tens of hours. The design process for most systems being modelled may be considered an optimisation process in so far as the design is improved based upon a comparison of the test results with a specification. Development of software to automate this process permits the improvements to continue outside working hours, and produces decisions unaffected by the psychological state of a human operator. Improved performance of simulation tools would facilitate exploration of more variations on a design, which would improve understanding of the problem domain, promoting a virtuous circle of design. The minimization of execution time was achieved through the development of a Parallel TLM Solver which did not use specialized hardware or a dedicated network. Its design was novel because it was intended to operate on a network of heterogeneous machines in a manner which was fault tolerant, and included a means to reduce vulnerability of simulated data without encryption. Optimisation processes were controlled by genetic algorithms and particle swarm optimisation which were novel applications in communication cable design. The work extended the range of cable parameters, reducing conductor diameters for twisted pair cables, and reducing optical coverage of screens for a given shielding effectiveness. Work on the comparison of results introduced ―Colour maps‖ as a way of displaying three scalar variables over a two-dimensional surface, and comparisons were quantified by extending 1D Feature Selective Validation (FSV) to two dimensions, using an ellipse shaped filter, in such a way that it could be extended to higher dimensions. In so doing, some problems with FSV were detected, and suggestions for overcoming these presented: such as the special case of zero valued DC signals. A re-description of Feature Selective Validation, using Jacobians and tensors is proposed, in order to facilitate its implementation in higher dimensional spaces.

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-08-24T20:51:57Z No. of bitstreams: 1 RUAN DELGADO GOMES – TESE (PPGEEI) 2017.pdf: 20190080 bytes, checksum: c170f5c01c9d6fd739d197414aee12e7 (MD5) / Made available in DSpace on 2018-08-24T20:51:57Z (GMT). No. of bitstreams: 1 RUAN DELGADO GOMES – TESE (PPGEEI) 2017.pdf: 20190080 bytes, checksum: c170f5c01c9d6fd739d197414aee12e7 (MD5) Previous issue date: 2017-06-14 / O uso de Redes de Sensores sem Fio Industriais (RSSFIs) para implementar aplicações de monitoramento ou controle apresenta vantagens em comparação ao uso de redes cabeadas, como a maior flexibilidade e o menor custo de implantação. No entanto, é necessário lidar com problemas típicos das redes sem fio, como interferência e o alto nível de atenuação em pequena e larga escala. Além disso, as características do canal sem fio variam com o tempo e uma RSSFI deve ser capaz de se adaptar a essas variações para manter boa qualidade de serviço durante sua operação. Estratégias adaptativas, como a alocação dinâmica de canais, permitem lidar com os problemas mencionados. Para isso, o primeiro passo é estimar a qualidade dos enlaces, de modo que os nós da rede possam decidir se uma mudança de canal é necessária. Esta tese apresenta como contribuição um novo estimador de qualidade de enlace (LQE) e um novo tipo de nó, o nó LQE, que estima a qualidade dos enlaces em tempo real, usando informações obtidas a partir do transceptor, e informações extraídas de pacotes de dados recebidos. O estimador proposto considera problemas causados pelo perfil de multipercurso do ambiente na qualidade do canal,interferência e assimetria. Um protótipo foi desenvolvido e a solução foi validada por meio de experimentos em um ambiente industrial real. Diferente de outros LQEs encontrados na literatura, a solução proposta não gera tráfego extra na rede e não causa sobrecarga nos nós finais. Com base no LQE proposto, um novo protocolo de acesso ao meio foi desenvolvido. O protocolo usa adaptação de canal para a transmissão de pacotes de dados e salto em frequência para a transmissão de pacotes em broadcast. A taxa de recepção de pacote média na camada de aplicação permaneceu perto do pico para todos os cenários avaliados com o protocolo proposto, mesmo considerando as variações na qualidade dos canais ao longo do tempo. Os resultados indicam que o protocolo proposto apresenta desempenho superior aos protocolos de acesso ao meio definidos pelos padrões para RSSFI, em termos de confiabilidade e determinismo. Vários resultados experimentais obtidos em ambientes industriais também são descritos e é proposto um novo modelo para simulação de protocolos multicanais. O modelo é capaz de capturar os efeitos de atenuação por multipercurso, sombreamento, assimetria, as características não estacionárias do canal sem fio e a descorrelação entre diferentes canais. / Industrial Wireless Sensor Networks (IWSNs), that is used to implement monitoring and control applications, presents certain advantages when compared to wired networks, including higher flexibility and lower deployment costs. However, it is necessary to deal with typical problems of wireless networks, such as interference and a high attenuation, in small and large scale. In addition, the characteristics of the wireless channel may change over time, and an IWSN needs to self adapt to these variations to maintain a good quality of service during its operation. Adaptive mechanisms, such as, dynamic channel allocation, are used to deal with the aforementioned problems. For this, the first step is to estimate the link quality, so that the network nodes can decide if a channel change is needed. This thesis presents as a contribution a novel Link Quality Estimator (LQE), and a new type of node, the LQE node, that estimates the quality of the links in real-time, using information obtained from the transceiver, and information obtained from received data packets. The proposed LQE deals with the problems caused by the multipath profile of the environment in channel quality, interference and asymmetry. A prototype was developed and the LQE was validated by experiments in an actual industrial environment. Different from other LQEs in the literature, the solution proposed in this thesis does not cause overhead at the end-nodes and on the network. Based on the proposed LQE, a novel MAC protocol was developed. The protocol uses channel adaptation for the transmission of unicast data packets, and frequency hopping for the transmission of broadcast packets. The packet reception rate at the application layer was at the peak for all scenarios that were evaluated using the proposed protocol, even considering the variations in channel quality over time. The results indicate that the proposed protocol presents a better performance in comparison to the MAC protocols defined by the standards for IWSN, in terms of reliability and determinism. Several experimental results obtained in industrial environments are also described, and a new model for simulation of multi-channel protocols is proposed. The model includes the effects of multipath fading, shadowing, asymmetry, the non-stationary characteristics of the channel, and the uncorrelation of the different channels.